Expression of CXCR4, E-cadherin, Bcl-2, and survivin in Merkel cell carcinoma: an immunohistochemical study using a tissue microarray.

Merkel cell carcinoma (MCC) is a rare but highly aggressive cutaneous malignancy with a mortality rate exceeding that of melanoma. Although smaller studies of markers of progression have been performed, large-scale investigation has been difficult due to the rarity of this tumor. Investigation of 4 potential immunohistochemical progression markers using an MCC tissue microarray was performed. An immunohistochemical analysis of CXCR4, E-cadherin, Bcl-2, and Survivin was performed on a tissue microarray of two hundred twenty-seven 0.6-mm tumor cores-110 primary, 73 local/regional metastatic, and 44 distant metastatic-from 87 patients, 23 of which were sampled 2 or more times. There was a statistically significant increase in immunoreactivity to CXCR4 and Survivin in local/regional nodal MCC metastases compared with primary and distant metastatic lesions. No significant differences by disease location were found for either Bcl-2 or E-cadherin. These results suggest a potential role for CXCR4 and Survivin in MCC tumor progression. However, previous data from other studies suggesting a role for Bcl-2 and E-cadherin in MCC progression are not confirmed in this larger sample. Further discovery of additional markers are needed to better characterize this rare but deadly malignancy.